No, you're right... you definitely don't want to hang an instrument like that from a scissor clamp.

And I fully understand not wanting to give up the floor real estate.

You could do what I did in my own edit suite, where I hung a big monitor, and also have a drop ceiling (which apparently you do, too). This is a 42' monitor (not gigantic by today's standards, but pretty big), and it is a plasma montior, not one of today's light-as-a-feather LEDs or LCDs... this guy is heavy.

This montitor hangs on a piece of pipe... just steel plumbing pipe, actually... and goes up through the ceiling tile where it is attached to the joists between floors. I couldn't find a commercial "real" hanging system for the monitor, so I hit Home Depot and built this...

You could hang an anvil off of it. Behind the scenes (or rather, above the tile), it looks like this....

It's just plumbing pipe, and a couple of T-connectors. The pipe runs through holes I drilled in the floor joists above, and one of the T-connectors allows for an easy cable pass to the monitor.

So yeah, a Source Four is heavy... but I really don't know another instrument that will give you that kind of punch and that kind of throw from that distance, and be super adjustible and take gobo patterns. It's really exactly what that light was made for. There could be smaller/lighter fixtures out there that will do similar, but I don't know what they are. If you are willing to give up pattern projection and some adjustability almost any one of a zillion different little fresnel instruments would work... but no patterns.